Background and Aim: Anaplasma platys is a blood parasite that infects platelets, causing thrombocytopenia. Rhipicephalus sanguineus ticks are believed to transmit A. platys. To identify A. platys, nested polymerase chain reaction (PCR) has proven to be an effective diagnostic tool. In this study, the molecular prevalence of A. platys infection in dogs was investigated for the 1st time in the Khon Kaen region of Thailand. The association between risk factors and A. platys infection was also evaluated. Materials and Methods: A total of 130 blood samples were collected from dogs in Khon Kaen, Thailand. DNA from the samples was extracted and nested PCR was applied for molecular analysis. Platelet count and packed cell volume (PCV) levels were measured. Platelet counts were categorized into four grades: Non-thrombocytopenia (platelets >200,000 cells/μL), mild thrombocytopenia (platelets 150,000-200,000 cells/μL), moderate thrombocytopenia (platelets 100,000-150,000 cells/μL), and severe thrombocytopenia (platelets <100,000 cells/μL). Four categories for PCV levels of >37%, 30-37%, 20-29%, and <20% were defined as no anemia, mild anemia, moderate anemia, and severe anemia, respectively. DNA sequencing was analyzed using BTSeq™ (Barcode-Tagged Sequencing; CELEMICS, Seoul, South Korea) for similarity index. Results: Among the 130 samples, 9 (6.9%) were positive for A. platys infection. There was an association between low platelet count and infection (p<0.05). PCV level was also associated with A. platys infection (p<0.05). DNA sequencing results of the nine positive samples showed similarity to known sequences of A. platys with 99.36-100% nucleotide identity. These results suggested low genetic diversity in A. platys infecting dogs in the Khon Kaen area. Conclusion: By amplifying 16S rRNA, A. platys infection was detected in the blood of Thai dogs. Further work should be performed to identify risk factors potentially associated with A. platys infection in dogs in Khon Kaen. Other related factors should also be considered, such as location and breeding, as well as the environmental characteristics of each locality. In addition, sampling a larger number of animals may reveal predictors for the positivity of A. platys in dogs in this region.

Background and Aim: Ehrlichia canis is a well-known cause of both anemia and thrombocytopenia in dogs. There are insufficient epidemiological data on this blood parasite in Thailand and the association of infections with hematological abnormalities. This study aimed to analyze the molecular characteristics and to identify E. canis as well as the risk factors associated with E. canis infection in dogs in Khon Kaen, Thailand. Materials and Methods: Blood samples from 126 dogs that visited animal clinics were subjected to molecular detection using nested polymerase chain reaction for E. canis 16S rRNA gene. The risk factors and hematological profiles associated with the infection were analyzed using the logistic regression test in program SPSS version 19. Results: Forty-one dogs were infected, indicating a 32.5% molecular infection rate of E. canis. The factors significantly associated with E. canis infection include animal housing status, low packed cell volume, low red blood cell count, and low platelets (p<0.05). Ten positive samples were amplified, sequenced, and phylogenetically analyzed. Sequence and phylogenetic analysis confirmed the current ten samples as E. canis compared with reference sequences in GenBank, using the BLAST program hosted by NCBI, which showed 99.74-100% similarity. Conclusion: This study provided the first data of infection rate of E. canis using nested PCR and molecular characteristics of E. canis in randomly selected domestic dogs in Khon Kaen, Thailand.